This invention relates generally to cooking appliances such as cooktops and ranges and more particularly to cooling various electronic components in such appliances.
Modern cooking appliances increasingly incorporate electronic control systems for controlling operation of the appliance. These control electronics are ordinarily contained in a separate control box located in close proximity to the heated elements of the cooking appliance. Because the control electronics cannot survive the elevated temperatures generated by the cooking appliance, cooling air is blown through the control box for cooling the electronics therein. The spent cooling air is discharged outside of the appliance. To enhance the functionality of the electronic control system, various sensors and other electronics are also being utilized. These additional components are often placed in close proximity to the heated elements of the cooking appliance.
Extensive use of electronics is particularly common in cooking appliances having a glass-ceramic plate as the cooking surface. The glass-ceramic plate presents a pleasing appearance and is easily cleaned in that its smooth, continuous surface lacks seams or recesses in which debris can accumulate. The glass-ceramic plate also prevents spillovers from falling onto the heating elements below. Such cooking appliances typically include a number of heating units mounted under a smooth glass-ceramic plate. A utensil placed on the glass-ceramic plate is directly heated by energy radiated from the appropriate heating unit. Alternatively, the glass-ceramic plate is sufficiently heated by the heating unit so that the utensil is heated by conduction from the heated glass-ceramic plate.
In either case, provision should be made to avoid overheating the glass-ceramic plate. For most glass-ceramic materials, the operating temperature should not exceed 600-700xc2x0 C. for any prolonged period. Under normal operating conditions, the temperature of the glass-ceramic plate will generally remain below this limit. However, conditions can occur that can cause this temperature limit to be exceeded. Commonly occurring examples include operating the appliance with a small load or no load (i.e., no utensil) on the cooking surface, using badly warped utensils that make uneven contact with the cooking surface, and operating the appliance with a shiny and/or empty utensil.
To protect the glass-ceramic plate from extreme temperatures, glass-ceramic cooktop appliances ordinarily have some sort of temperature sensor for monitoring the temperature of the glass-ceramic plate. If the glass-ceramic plate approaches its maximum temperature, the power supplied to the heating unit is reduced to prevent overheating. In addition to providing thermal protection, such temperature sensors can be used to provide temperature-based control of the cooking surface and to provide a hot surface indication, such as a warning light, after a burner has been turned off.
It is common to locate a temperature sensor beneath each heating unit. The temperature sensors are thus subject to the high temperatures generated in the appliance. Other types of sensors provided to enhance the functionality of the electronic control system are typically located in the hot regions of the appliance. Such sensors include sensors for detecting characteristics, such as the temperature, size or type, of a utensil placed on the cooking surface, sensors for detecting the presence or absence of a utensil, and sensors for detecting properties such as boiling state of the utensil contents.
These sensors are susceptible to failure because of the high temperatures they are exposed to. Accordingly, it is desirable to provide a cooking appliance in which temperature and other sensors are cooled to prolong their life.
The above-mentioned need is met by the present invention, which provides a cooking appliance comprising a burner box having an air inlet and at least one burner assembly disposed therein. A control box containing control electronics is located adjacent to the burner box. The control box is provided with an air inlet and an air outlet for permitting a flow of cooling air therethrough. Also provided are means for causing cooling air to pass through the control box. The burner box air inlet is positioned so that cooling air exiting the control box via the control box outlet enters the burner box via the burner box inlet. In one preferred embodiment, an inner box is disposed in the burner box so as to define a compartment into which the cooling air flows.
The present invention and its advantages over the prior art will become apparent upon reading the following detailed description and the appended claims with reference to the accompanying drawings.